<!doctype html>
<html lang="en">
	<head>
		<meta charset="UTF-8" />
		<meta http-equiv="X-UA-Compatible" content="IE=edge" />
		<meta name="viewport" content="width=device-width, initial-scale=1.0" />
		<title>margin</title>
	</head>

	<body>
		<section class="container">
			<section class="main"></section>
			<section class="footer"></section>
		</section>
		<style>
			* {
				margin: 0;
			}

			.container {
				height: 100vh;
				display: flex;
				flex-direction: column;
			}

			.main {
				flex: 0 0 700px;
				background-color: aquamarine;
			}

			.footer {
				flex: 0 0 100px;
				background: deeppink;
				margin-top: auto;
			}
		</style>
	</body>
</html>
